NOTE:
The image samples are 100% crops of full images. There was NO
image editing performed to any of the below crops. I only resized
and sharpened thumbnail examples to better represent
how the images should look in real life.

All
full size images were 16-bit Tiffs converted from RAW files.
The parameters used were: Normal sharpness, Normal contrast
and Normal saturation.

Introduction

Prior
to the release of the new 16-35mm f/2.8L, the Canon 17-35mm
f/2.8L lens was the professional photographer's only choice
for the ultra wide zoom range. Both are excellent choices considering
the flexibility and image quality they provide.
However, some people have expressed negative comments about
the 17-35L, particularly about the image quality when shooting
wide open. I found that the 17-35L can sometimes produce soft
images when certain focal lengths are combined with large apertures.
For example, when shot at 35mm f/2.8, images are noticeably
softer than when shot at 20mm f/2.8. From my own tests, the
best focal length and aperture combinations are in the range
of 17-24mm at f/5.6-11.

Although
the short ranges of the lens perform well, there are serious
problems with distortion at 17mm. (about 6%). This makes the
lens unsuitable for architecture photography.

Enough
said. Let's compare it to the new Canon EF 16-35mm f/2.8L.Click
below for full specifications straight from Canon's site:

Below
is a quick gif animation that shows how much wider one millimeter
looks in the wide-angle range. If you add in the D30 multiplier,
you are looking at a 25.6mm verses 27.2mm. Just enough difference
to make it a good reason for D30 users to upgrade.

Physical
comparison

When
I held the two lenses side by side, I found that the new 16-35L
was built significantly better. It reminds me of the build quality
of the 135mm f/2L lens. Perhaps Canon heard our cries when we
asked for superior construction, and higher quality material
in the body. This ultra wide-angle lens lives up to the L-series
standards.

The
body finish appears more durable and stronger against the rather
plastic-like finish of the 17-35L lens. As you can see from
the above picture, the new 16-35L is almost a 1/2 inch taller.
However, they weight about the same with the 16- 35L only a
mere 50g heavier.

The
included 16-35L lens hood (EW-83E) is slightly larger and longer
than the 17-35L's (EW-83CII). It seems like this design difference
will help combat flare more efficiently.

AF comparison

When comparing the auto focus speed, I found that Canon used
the same inner focusing system with USM in both lenses. Upon
first glance, the 16-35L AF speed seems similar to the 17-35L
AF speed. I recently tested the new lens with the Canon D30
and noticed a slight AF speed advantage with the 16-35L, especially
in low light.

Another
added feature of the 16-35L is its closest focusing distance.
Canon was able to practically cut the minimal focusing distance
in half. The new zoom's minimal focusing distance is now 0.28m/0.9ft
against 0.42m/1.4ft.

Here
is an example of how close the 16-35mm f/2.8L can achieve focus
comparing to the 17-35L.

17-35L
@ 17mm -- closest focusing distance

16-35L
@ 16mm -- closest focusing distance

Optical
quality

.Below
is a comparison between the 16-35L and 17-35L using small apertures.
I am most interested in this comparison since I often use f/8
and f/18 when shooting landscape.

17-35L
@ 17mm f/8

16-35L
@ 17mm f/8

17-35L
@ 17mm f/18

16-35L
@ 17mm f/18

As
you can see from the above 100% crops, the new 16-35mm f/2.8L
has an edge over the 17-35L in terms of sharpness and contrast
at small apertures. Keep in mind that images tend to be softer
when shooting at >f/11 apertures due to diffraction. Landscape
photography is full of compromises.

Below,
I compared the differences between the 16-35L and 17-35L when
shooting wide open. I was optimistic about how the new 16-35mm
f/2.8L would perform wide open since it is the first EF wide-angle
zoom to combine three aspherical elements with Canons
UD glass.

17-35L
@ 17mm f/2.8

16-35L
@ 16mm f/2.8

As
you can see from the above example, the new 16-35L performs
MUCH BETTER wide open when compared to the 17-35L. I'm impressed!

This
final example demonstrates the difference between images shot
at f/8 and f/2.8 with the new 16-35mm f/2.8L

16-35L
@ 16mm f/2.8

16-35L
@ 16mm f/8

These
results confirm that the 16-35mm f/2.8L is a worthy upgrade
from the 17-35L. The wide open (f/2.8) image quality comes close
to the f/8 sweet spot aperture of the lens.

Conclusion

If
you are in the market for a new wide-angle lens, I definitely
recommend spending the extra $250 and getting the new 16-35L.
In terms of sharpness, contrast, and extra features, you will
get your monies worth. The new lens has less distortion at 16mm
than the previous 17-35L at 17mm. Another welcome improvement
is the 16-35L's ability to focus at 0.28m/0.9ft.
For those of you who already own a 17-35L and are disappointed
by its performance wide open, now you have a viable choice to
achieve sharp images at that aperture setting.

Overall,
this is one of the sharpest super wide-angle zoom lenses that
I have ever tested. I recommend it!